Bug 155367 – Python test webkitpy.common.system.executive_unittest.ExecutiveTest.serial_test_kill_process is flaky

• Status: RESOLVED
• Resolution: FIXED
• Component: New Bugs

[Ryan Haddad]

webkitpy.common.system.executive_unittest.ExecutiveTest.serial_test_kill_process is flaky

This webkitpy test has been flaky and failing intermittently.

https://build.webkit.org/builders/Apple%20El%20Capitan%20Release%20WK2%20%28Tests%29/builds/4200
https://build.webkit.org/builders/Apple%20El%20Capitan%20Release%20WK2%20%28Tests%29/builds/4168
https://build.webkit.org/builders/Apple%20El%20Capitan%20Release%20WK2%20%28Tests%29/builds/4156

https://build.webkit.org/builders/Apple%20iOS%209%20Simulator%20Release%20WK2%20%28Tests%29/builds/3909
https://build.webkit.org/builders/Apple%20iOS%209%20Simulator%20Release%20WK2%20%28Tests%29/builds/3893
https://build.webkit.org/builders/Apple%20iOS%209%20Simulator%20Release%20WK2%20%28Tests%29/builds/3886

[1446/1451] webkitpy.common.system.executive_unittest.ExecutiveTest.serial_test_kill_process failed:
  Traceback (most recent call last):
    File "/Volumes/Data/slave/elcapitan-release-tests-wk2/build/Tools/Scripts/webkitpy/common/system/executive_unittest.py", line 184, in serial_test_kill_process
      self.assertEqual(process.wait(), expected_exit_code)
  AssertionError: 0 != -15

[Alexey Proskuryakov]

I think that this was introduced by this change, unclear if it was even intentional: <http://trac.webkit.org/changeset/89400/trunk/Tools/Scripts/webkitpy/common/system/executive.py>

Doing a non-blocking waitpid followed by another waitpid is super racy, and no wonder that the second one sometimes fails.

Can't say that I like overall design of this code either - it relies on an exception as part of normal operation.

[Alexey Proskuryakov]

Created attachment 276272 [details]
proposed fix

Tests pass on Mac without this. I didn't test on Windows.

[WebKit Commit Bot]

Attachment 276272 [details] did not pass style-queue:


ERROR: Tools/ChangeLog:1:  ChangeLog entry has no bug number  [changelog/bugnumber] [5]
Total errors found: 1 in 1 files


If any of these errors are false positives, please file a bug against check-webkit-style.

[Alexey Proskuryakov]

Created attachment 276276 [details]
proposed fix

With a proper ChangeLog.

[WebKit Commit Bot]

Comment on attachment 276276 [details]
proposed fix

Clearing flags on attachment: 276276

Committed r199403: <http://trac.webkit.org/changeset/199403>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.